Sources told ESPN’s Pedro Gomez that Strasburg told Baker he is feeling much better and could start. Sources said that Strasburg was on the first bus to the stadium, and four hours before game time, Baker, general manager Mike Rizzo and team management were working on a decision.

Game 4 of the NLDS was postponed from Tuesday to Wednesday because of rain, leading to speculation that Game 1 starter Strasburg could take the mound on his regular four days’ rest. But Baker cited illness and routine in saying that he was sticking with Tanner Roark.

Baker said Tuesday that, in addition to Strasburg, several of his players were ill.

Keep up with the latest as baseball’s top teams contend for the title.

“A lot of my team is under the weather with the change of weather, and the air conditioning in the hotel, and the air conditioning here,” he said. “It’s just this time of the year for mold around Chicago — I think it’s mold. I mean, I have it too.”

Given how dominant Strasburg has been, and given the Cubs hold a 2-1 lead in the best-of-five series, it seemed likely that Baker would opt to skip Roark and go with Strasburg on full rest.

After the All-Star break, Strasburg posted a 0.86 ERA, the second-lowest ever by a pitcher in the second half of a season (minimum 10 starts). Then, in the NLDS opener last Friday, the 29-year-old right-hander was dominant, allowing three hits and no earned runs over seven innings, striking out 10 in a 3-0 defeat.

But despite Strasburg’s effectiveness, and despite facing elimination, Baker said Tuesday that Roark would get the nod Wednesday at Wrigley.

“Well, we decided to stay with Tanner because, No. 1, you know, he was slated [to pitch Tuesday],” Baker said.

Baker said Strasburg threw a bullpen session Tuesday, which would typically line him up to pitch Thursday for a potential Game 5. But a Nationals spokesperson later Tuesday said Baker misspoke and that Strasburg’s bullpen session actually took place Monday, and that the primary reason the former top pick wouldn’t start Wednesday was because he isn’t feeling well.

“Didn’t work out for Stras for his bullpen day, and we’re all creatures of habit, and plus, we’ve got full confidence in Tanner,” Baker said. “And Stras, it would have been better, because he’s feeling under the weather, like a lot of my team is. So this day actually comes as a plus for our team.”